Chapter 1: Minerals of the Earth’s Crust

A mineral is a naturally occurring, inorganic solid that has a definite chemical composition and a crystal structure.

A mineral’s atoms are arranged in a regular, repeating pattern A mineral’s atoms are arranged in a regular, repeating pattern. This is called a crystal pattern. Every mineral has its own characteristic crystal structure, which makes them easy to identify.

Minerals have certain physical properties that can be used to identify them. 1. color: some minerals have a characteristic color, which makes them easy to identify. Many minerals can appear as different colors, so this isn’t the best property to use. 2. luster: this is the unique way that a mineral reflects light. Luster can be either metallic (shiny) or nonmetallic (dull)

3. hardness: the ability to resist being scratched 3. hardness: the ability to resist being scratched. Hardness is measured using the Mohs Scale (1-10).

4. streak: the color of the powder of a mineral when scratched on a hard surface. This can be very different than the color of the mineral!

5. cleavage, fracture: these terms describe how a mineral breaks 5. cleavage, fracture: these terms describe how a mineral breaks. Cleavage is when a rock breaks along a flat, smooth surface. Fracture is when the rocks break along a jagged, rough surface.

Minerals have been an important resource for thousands of years Minerals have been an important resource for thousands of years! Today, minerals serve as raw materials for many common everyday products. Ore: a naturally occurring, combination of both metals and nonmetals.

Metals: shiny surfaces, good conductors of heat and electricity, malleable, ductile Nonmetals: dull surfaces, poor conductors of heat and electricity, brittle

Gemstones: a mineral that can be cut and polished for jewelry Gemstones: a mineral that can be cut and polished for jewelry. These are very rare, and are usually very expensive! Ex- diamond Blue Diamond: 7.8 million US dollars!